normality test

Currently, I'm doing a research using Beck Depression Inventory on 340 respondents from my university. Before I apply any parametric tests, I tested the normality first, however the normality is not assumed. So, I wondering is the data really not normal or the way I analyze it have problem ...

I often see that for parametric tests one assumption is that the population should be normally distributed. However if I understand correctly the central limit theory shows that the distribution of the sample means (the sampling distribution) has a normal distribution, irrespective of the...

Hello everyone,
I am checking my assumptions before running an ANCOVA, one of which is that the DV is normally distributed across all levels of the IV. MY IV is 3 groups (Ns of 32, 31, and 32) and my DV is a continuous variable from 1 - 5. Before splitting into groups, it looks normal and the...

I'm looking for Visual Basic source code that will, after entering the data of a distribution, test that distribution for being normal or 'almost' normal.
Alternatively, I am looking for step by step instructions for such a test, so that I will be able to create the source code myself.
Thanks.

Hi all!
this is probably a simple question; however, my statistics skills got a bit rusty and I cannot find an appropriate solution on the internet...
This is the problem: Let X_1, ..., X_n be a series of values drawn from a normal distribution. All I know about them is their mean u=sum...

I have found mixed information in regard to the number of degrees of freedom used to evaluate the chi2 statistics derived to check the normality of a given data set.
In one case I found that df = Nbins - 3 and in other cases I have found df = Nbins-1
The idea of this test is to divide the...

Hello there.
I am testing my data distribution for normality using both Shapiro Wilk and Kolmogorov and Smirnov tests in SPSS.
S&W reveals that the data is not normally distributed whereas K&S shows its approximately normally distributed.
How can i justify the use of K&S over S&W in order to...

Hello there.
I have 5 Likert scale questionnaires that have been answered by the same people who have been randomly selected (N=24) and i have the following problem:
I first test the data distribution of each scale in order to determine what statistical analysis tests should i employ...

I am using proc mixed for my analysis (RCBD), but don't know the SAS code for outputting the residual which I can use for checking normality. Can anyone help me with the SAS code?
The code I'm using is:
proc mixed data=A;
class ID trt depth block;
model LogNO3= trt| depth;
random block...

Hello,
I'm a novice in stats, and I wanted to know how to normalize 'skewed' data. I work with SPSS and I went to transform>compute variable> and then I do a log transformation...
However, when I run the normality tests, I am still getting a significance of .000 for both the K-S and...

Good day everyone.
I'm a student who are currently doing her psychology research (final year project). I'm having an issue with my data being not normal. I have ran the test of normality(Shapiro Wilks test) using SPSS software and I found out that my p-value is 0.000 (not significant). And then...

Hi All,
I just ran the PROC MIXED for outputting the residual error in SAS [TO CHECK FOR NORMALITY]
I am wondering if I need to look at Shapiro-Wilk or Kolmogorov-Smirnov tests? My sample size is 217 [repeated at 3 time points]. So, when I check for the normality of the residual error, do I...

Hi everybody,
I would like to ask you something about the normality hypotesis on the residuals when performing an ANOVA. Do I have to check the entire residuals data set or, do I have to check normality of the residuals relative to each level of each IV (for example, 1 IV with 3 levels, 3...